Nachiguro-Ishi (Stone)

Nachiguro-stone, which comes from the valley on the upper stream of the Kumano river, has been used to make inkstones, go-pieces and ornamental stones and has an established reputation for its high quality.
Black go-pieces are especially famous throughout Japan and are actually known as Nachiguro.
It is said that their origin goes back to the Nara period (710-794).